McLaren has three Daniel Ricciardo reserves, including Alpine's Oscar Piastri, on stand-by

McLaren can choose from at least three drivers to replace COVID-stricken Daniel Ricciardo at the Bahrain Grand Prix, team principal Andreas Seidl said on Saturday, even though he expects the Australian to be fit in time for next weekend's Formula One season-opener.

The 32-year-old missed the opening two days of the final pre-season test in Bahrain after feeling unwell and then tested positive for COVID-19 on Friday evening, ruling him out of Saturday's final day of action.

Seidl, who was quoted by German publication Auto, Motor und Sport as saying Ricciardo would have to isolate until the evening of March 17, said he was confident the Australian would be back behind the wheel in time for the March 18-20 grand prix.

But he said McLaren had Stoffel Vandoorne and Nyck de Vries, reserve drivers for power unit supplier Mercedes, and Scot Paul di Resta as back-ups.

"In terms of reserve drivers, similar to previous years we have an agreement with Mercedes where we share reserve drivers," Seidl told reporters at the Sakhir circuit on Saturday.

"We also have Paul di Resta, similar to last year, on standby in case it's needed, but again, I expect Daniel to be back in good shape next week."

Vandoorne, who raced for McLaren in 2017 and 2018 and now drives for Mercedes in the Formula E series, is scheduled to compete in the 1000 Miles of Sebring endurance race on the same weekend as the Bahrain Grand Prix.

De Vries, Vandoorne's Formula E team mate, won the Formula Two title in 2019 but has never raced in Formula One.

Di Resta, who raced for Force India from 2011 to 2013, last competed in a Formula One race as a stand-in for Felipe Massa at Williams at the 2017 Hungarian Grand Prix.

Even if he is fit, Ricciardo will head into the Bahrain opener on the back foot.

He has had only a day and a half of experience, chalked up during the first pre-season test in Barcelona, in a car that has been designed to the most radical rules overhaul in decades.

"It definitely puts us and Daniel on the back foot as well," Seidl said. "But in the end that's something Daniel couldn't control, we simply have to accept that's how it is."